/*
 * Copyright (C) 2009 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;

import java.util.Comparator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.function.Function;
import java.util.stream.Collector;

/**
 * GWT emulation of {@link com.google.common.collect.ImmutableBiMap}.
 *
 * @author Hayward Chan
 */
public abstract class ImmutableBiMap<K, V> extends ForwardingImmutableMap<K, V>
        implements BiMap<K, V>
{
    public static <T, K, V> Collector<T, ?, ImmutableBiMap<K, V>> toImmutableBiMap(
            Function<? super T, ? extends K> keyFunction,
            Function<? super T, ? extends V> valueFunction)
    {
        return CollectCollectors.toImmutableBiMap(keyFunction, valueFunction);
    }

    // Casting to any type is safe because the set will never hold any elements.
    @SuppressWarnings("unchecked")
    public static <K, V> ImmutableBiMap<K, V> of()
    {
        return (ImmutableBiMap<K, V>) RegularImmutableBiMap.EMPTY;
    }

    public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1)
    {
        checkEntryNotNull(k1, v1);
        return new SingletonImmutableBiMap<K, V>(k1, v1);
    }

    public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2)
    {
        return new RegularImmutableBiMap<K, V>(ImmutableMap.of(k1, v1, k2, v2));
    }

    public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3)
    {
        return new RegularImmutableBiMap<K, V>(ImmutableMap.of(k1, v1, k2, v2, k3, v3));
    }

    public static <K, V> ImmutableBiMap<K, V> of(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4)
    {
        return new RegularImmutableBiMap<K, V>(ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4));
    }

    public static <K, V> ImmutableBiMap<K, V> of(
            K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5)
    {
        return new RegularImmutableBiMap<K, V>(ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5));
    }

    public static <K, V> ImmutableBiMap<K, V> of(
            K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6)
    {
        return new RegularImmutableBiMap<K, V>(
                ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6));
    }

    public static <K, V> ImmutableBiMap<K, V> of(
            K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7)
    {
        return new RegularImmutableBiMap<K, V>(
                ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7));
    }

    public static <K, V> ImmutableBiMap<K, V> of(
            K k1,
            V v1,
            K k2,
            V v2,
            K k3,
            V v3,
            K k4,
            V v4,
            K k5,
            V v5,
            K k6,
            V v6,
            K k7,
            V v7,
            K k8,
            V v8)
    {
        return new RegularImmutableBiMap<K, V>(
                ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8));
    }

    public static <K, V> ImmutableBiMap<K, V> of(
            K k1,
            V v1,
            K k2,
            V v2,
            K k3,
            V v3,
            K k4,
            V v4,
            K k5,
            V v5,
            K k6,
            V v6,
            K k7,
            V v7,
            K k8,
            V v8,
            K k9,
            V v9)
    {
        return new RegularImmutableBiMap<K, V>(
                ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9));
    }

    public static <K, V> ImmutableBiMap<K, V> of(
            K k1,
            V v1,
            K k2,
            V v2,
            K k3,
            V v3,
            K k4,
            V v4,
            K k5,
            V v5,
            K k6,
            V v6,
            K k7,
            V v7,
            K k8,
            V v8,
            K k9,
            V v9,
            K k10,
            V v10)
    {
        return new RegularImmutableBiMap<K, V>(
                ImmutableMap.of(
                        k1, v1, k2, v2, k3, v3, k4, v4, k5, v5, k6, v6, k7, v7, k8, v8, k9, v9, k10, v10));
    }

    @SafeVarargs
    public static <K, V> ImmutableBiMap<K, V> ofEntries(Entry<? extends K, ? extends V>... entries)
    {
        return new RegularImmutableBiMap<K, V>(ImmutableMap.ofEntries(entries));
    }

    public static <K, V> Builder<K, V> builder()
    {
        return new Builder<K, V>();
    }

    public static final class Builder<K, V> extends ImmutableMap.Builder<K, V>
    {

        public Builder()
        {
        }

        Builder(int initCapacity)
        {
            super(initCapacity);
        }

        @Override
        public Builder<K, V> put(K key, V value)
        {
            super.put(key, value);
            return this;
        }

        @Override
        public Builder<K, V> put(Entry<? extends K, ? extends V> entry)
        {
            super.put(entry);
            return this;
        }

        @Override
        public Builder<K, V> putAll(Map<? extends K, ? extends V> map)
        {
            super.putAll(map);
            return this;
        }

        @Override
        public Builder<K, V> putAll(Iterable<? extends Entry<? extends K, ? extends V>> entries)
        {
            super.putAll(entries);
            return this;
        }

        public Builder<K, V> orderEntriesByValue(Comparator<? super V> valueComparator)
        {
            super.orderEntriesByValue(valueComparator);
            return this;
        }

        Builder<K, V> combine(Builder<K, V> other)
        {
            super.combine(other);
            return this;
        }

        @Override
        public ImmutableBiMap<K, V> build()
        {
            return buildOrThrow();
        }

        @Override
        public ImmutableBiMap<K, V> buildOrThrow()
        {
            ImmutableMap<K, V> map = super.buildOrThrow();
            if (map.isEmpty())
            {
                return of();
            }
            return new RegularImmutableBiMap<K, V>(super.buildOrThrow());
        }

        @Override
        ImmutableBiMap<K, V> buildJdkBacked()
        {
            return build();
        }
    }

    public static <K, V> ImmutableBiMap<K, V> copyOf(Map<? extends K, ? extends V> map)
    {
        if (map instanceof ImmutableBiMap)
        {
            @SuppressWarnings("unchecked") // safe since map is not writable
            ImmutableBiMap<K, V> bimap = (ImmutableBiMap<K, V>) map;
            return bimap;
        }

        if (map.isEmpty())
        {
            return of();
        }

        ImmutableMap<K, V> immutableMap = ImmutableMap.copyOf(map);
        return new RegularImmutableBiMap<K, V>(immutableMap);
    }

    public static <K, V> ImmutableBiMap<K, V> copyOf(
            Iterable<? extends Entry<? extends K, ? extends V>> entries)
    {
        return new Builder<K, V>().putAll(entries).build();
    }

    ImmutableBiMap(Map<K, V> delegate)
    {
        super(delegate);
    }

    public abstract ImmutableBiMap<V, K> inverse();

    @Override
    public ImmutableSet<V> values()
    {
        return inverse().keySet();
    }

    public final V forcePut(K key, V value)
    {
        throw new UnsupportedOperationException();
    }
}
